Britain’s leading energy providers are under fire again after missing a deadline to help households with smart meters avoid being hit with unexpected bills.

Electricity and gas suppliers, including the big six and smaller providers, had pledged that by the end of 2016 they would cut back on sending backdated or catchup bills to customers whose smart meters inaccurately measured their energy usage. However, not one of the big six or dozens of smaller suppliers have met the self-imposed target of cutting the limit for back-bills from 12 months to six months.

Every UK home is due to be fitted with a smart meter within four years. These meters provide accurate, real-time billing information to households about their fuel usage, doing away with the need for estimated readings. However, some of the 2 million households already fitted with them experience problems with their accuracy, meaning they can receive demands from their energy provider to make extra payments to cover their actual usage.

The energy regulator Ofgem, which has described the plan to cut backdated bills as a “significant improvement for consumers”, said it was considering whether further steps were needed to protect billpayers as a result of the failure to meet the deadline.

Citizens Advice, the consumer group, called on Ofgem to make the six-month limit a regulatory requirement for energy companies. Gillian Guy, chief executive of Citizens Advice, said: “Smart meters should signal the end of inaccurate bills and it’s not right that people with this technology should suffer because of suppliers’ mistakes. Setting a limit on the time period for which suppliers can send catchup bills for smart meters will give people greater protection when things go wrong.”

Citizens Advice said 402 of the 1,500 smart-meter issues it had helped with last year were related to billing. That was more than double the amount in 2015, a reflection of the increasing number of homes with the meters.

Their accuracy came to the fore earlier this month after a glitch meant the in-home displays of some SSE smart meter customers showed daily bills of more than £30,000. However, SSE said people were still able to get correct readings via its website, and it is rolling out a software update to fix the affected displays.

In theory, smart meters should do away with surprise bills as they do not use estimated readings or rely on customers submitting regular readings. But technical problems, such as a meter not being able to communicate data back to the supplier, can mean people still get landed with hefty back-bills. Citizens Advice said one woman received a bill of £1,900, more than a year after having a smart meter installed, because it had not been configured correctly.

Several readers told the Guardian of smart meters that had been installed but had failed to send readings back to their supplier. Ian Nock, who runs a consultancy, said his supplier had installed a smart meter despite it being located in his basement where it was unable to get a signal. As a result he is still having to submit readings manually.

Energy UK, the trade body that represents energy suppliers, said its members had not cut smart meter back-billing from 12 months to six months yet because of the Data Communications Company, the body set up to handle the data.

A spokesman for Energy UK said: “While the DCC has gone live, it’s not fully operational and testing is ongoing. In order to confirm that the system is stable, we would need DCC live operations launched, working with a volume of meters working smoothly on DCC systems.”

The DCC switched on later than planned in November. However, a spokesman for the body, which is run by FTSE 100 support services group Capita, said it was now operating smoothly.

The energy companies told Ofgem last year (pdf) they would move to a six-month back-billing limit “subject to the necessary operational infrastructure being in place and stable, following DCC go-live”. They added: “On current plans, this would mean the limit taking effect around the end of 2016.”

A spokesman for Ofgem said: “We want to see energy suppliers making progress towards implementing a lower limit on back-billing for customers with smart meters and are monitoring progress of this very closely. We are currently considering whether to take further steps to protect consumers.”

Smart Energy GB, the organisation tasked with handling the switchover to smart meters, said the devices would eventually use a dedicated communications network rather than relying on the mobile phone network, which would help to solve the problems.

The latest figures show that by October last year there were 4.05m meters installed in homes, roughly 8% of households.

One customer’s £1,900 bill

Lydia had a smart meter fitted in April 2015, but was concerned it was not working properly when it told her she was still in credit. She repeatedly contacted her supplier, Ovo, over a 14-month period about the meter. At the end of 2015 an engineer visited and confirmed the meter was not configured correctly.

In June 2016, Lydia received a bill of £1,900 for energy use at her three-bed terraced house. She said the bill was higher than before she began using the smart meter. After her case was taken up and publicised by Citizens Advice, Ovo eventually cancelled her debt.